The present invention relates to a device for closing an opening in a chamber wall of a low-pressure chamber or a vacuum chamber comprising:
at least one movably supported closure element and
at least one main body with a through-opening and at least one seat, which surrounds the through-opening, with the through-opening can be made congruent or is congruent with the opening in the chamber wall, and
at least one open position of the closure element, in which the through-opening is released by the closure element, and at least one closed position of the closure element, in which the through-opening is completely closed by the use of the closure element, and
at least one elastic seal with at least one inflatable chamber, with the seal in the closed position being arranged between the closure element and the seat and the closure element seals against the seat.
Low-pressure and/or vacuum chambers are frequently used in prior art to perform production or processing steps under low-pressure and/or vacuum. In order to allow inserting the work pieces to be processed into the low-pressure chamber and/or vacuum chamber openings are required in the chamber wall, which after inserting the object to be processed can be closed again, before the low-pressure and/or the vacuum is generated in the low-pressure and/or vacuum chamber. Generic devices serve to appropriately close these openings in the chamber wall of the low-pressure and/or vacuum chamber. Of course, these devices are embodied such that the object to be processed in the open state of the closure element not only can be inserted into the low-pressure and/or vacuum chamber but can also be removed therefrom. Generic devices may be produced as separate parts and fastened appropriately at the chamber wall. However, it is also possible to integrate the elements and/or their main body directly in the chamber wall. By fastening as well as by integration of the elements at or in the chamber wall, in any case the through-opening of the device is made congruent with the opening in the chamber wall, so that the work pieces to be processed can be guided through the through-opening into the device and the opening in the chamber wall when the closure element is in the opened position. In the closed position of the closure element the through-opening and thus also the opening in the chamber wall are completely closed. Closure elements of this type are available in very many different embodiments. Generic installations of this type provide at least one elastic seal, which exhibits an inflatable chamber, with the seal in the closed state being arranged between the closure element and the seat and seals the closure element to the seat. These so-called inflatable seals are advantageous such that they can compensate uneven sections in the seat to which they are pressed. Further, they allow the omission of any additional movement of the closure element in the direction towards the seat and in the direction away from the seat and this way permit a mechanically easier design of generic elements.
In prior art, various inflatable seals are known in the context with low-pressure and/or vacuum chambers. For example, it is known from U.S. Pat. No. 5,772,950 A to fasten the lid of a vacuum chamber via an inflatable seal to the remaining chamber wall of the vacuum chamber. US 2004/0123916 A1 as well as GB 1530977 A show similar installations. A device for electron-beam processing is known from U.S. Pat. No. 4,080,526 A in which also inflatable seals are used to seal a vacuum chamber.
One disadvantage of the inflatable seals lies in the fact that particularly by aging processes and the like the wall of the inflatable chamber in the seal can break, by which the leak developing here allows the fluids used for inflating the seal to penetrate during the processing step into the low-pressure chamber and/or the vacuum chamber. This leads generally not only to a disturbance of the process occurring in the low-pressure and/or vacuum chamber but, due to the high pressure differences, usually the object to be processed is destroyed or perhaps also the low-pressure and/or vacuum chamber itself is compromised and/or destroyed.